There are two basic types of catamenial tampons used for feminine hygiene currently available on the market, each of which are ideally designed to offer discreet and comfortable protection. The first type is a digital tampon which is designed as an absorbent structure to be inserted into a body cavity such as a woman's vagina, directly by a user's fingers. The second type is a tampon which is designed to be inserted with the aid of a separate applicator. Such applicators are typically manufactured of either paperboard or polymer materials. Both types of tampons can be made by folding or rolling a loosely associated strip or ribbon of absorbent material into an elongated or other shape, such as a “W”, “V” or cup-like shape, often referred to as a “blank” or “softwind,” in the case of a rolled ribbon. Such is described in U.S. Pat. No. 5,533,990 to Yeo. The softwind is then, in one configuration, either radially and/or biaxially compressed to form the processed tampon absorbent. A description of a method for making a radially wound absorbent is disclosed in U.S. Pat. No. 4,816,100 to Friese. The radial wound softwind may be compressed into a compacted absorbent like that disclosed in U.S. Pat. No. 6,310,269 to Friese.
A compressed absorbent structure is also known in the patent art as a “pledget”. In alternative tampon pledget designs, such as those described in U.S. Pat. No. 6,837,882, and US20080132868 to Jorgensen, the pledget is formed into a chevron-shaped structure and then compressed, or a perpendicularly overlapping layer configuration and then compressed/molded into a cup-like shape. Suitable methods for making “W”-folded pledgets or “V” -folded pledgets are disclosed in U.S. Pat. No. 6,740,070 to Agyapong; U.S. Pat. No. 7,677,189 to Kondo; and U.S. 2010/0114054 to Mueller. Each of the foregoing patents is hereby incorporated by reference in its entirety.
Each of the above described pledgets may or may not include a cover which will facilitate holding the absorbent material together once compressed. In both types of tampons (the digital or applicator), a withdrawal string is typically attached to the absorbent, either before or after compression, to facilitate removal of the tampon or insert from the user's vagina or other orifice, after it has absorbed a certain quantity of body fluid, such as urine, menses, blood, etc. The withdrawal string may be physically attached to the absorbent either through a bonding method, such as stitching, thermal, adhesive or other mechanical means, or alternatively, rather than being physically attached, it may be merely wrapped around the absorbent or a portion thereof, during the manufacturing process, and allowed to hang off of one end of the finished tampon absorbent (sometimes referred to as tampon “blank”).
As the various tampons described above are saturated by menses, they expand into a variety of shapes, depending on the initial tampon structure. It has been found that many of these differently shaped tampons, both digital as well as those delivered by an applicator, are often unable to prevent premature leakage of body fluid, that is leakage of menses from a user's vagina prior to the complete saturation of the tampon absorbent. Premature leakage, which often results from an inefficient use of tampon absorbent capacity, can result from a number of factors. For example, one factor is the tampon does not properly fit above the introital region of the vagina.
Another factor is that the tampon is not shaped correctly to intercept fluid flow through the vaginal canal. Still another factor is that the folds and convolutions of the vagina are not all in contact with the tampon absorbent and therefore body fluid is able to bypass the tampon. Still, a further reason for leakage lies in the absorbent fiber or layer construction of the tampon, such that the tampon design itself inadvertently interferes with maximum menses absorption. Yet a further factor is the residual menses which accumulates on the withdrawal end of a tampon during the withdrawal process and which exits the vagina at the onset of the tampon removal. Therefore, even if a tampon is shaped to prevent leakage in use, it has been found that leakage may still occur upon tampon absorbent withdrawal.
Further, since insertion stresses on a tampon absorbent may be different depending on whether a tampon absorbent is a digital or applicator-type tampon, there is a need for a tampon absorbent structure which can provide leakage protection for a variety of tampon formats. There is a need for a tampon absorbent which can provide the strength necessary to accommodate digital and applicator insertion and yet still allow for leakage protection.
It has also been found that tampon absorbents may not provide predictable comfort during use or withdrawal, as a result of their various expansion shapes over time. For example, tampon absorbents made from a single ribbon material or substantially overlapping sheet materials, have been found to sometimes result in inadequate customized fit. Even when such single ribbon tampon absorbents or substantially overlapped sheet materials are shaped and otherwise mechanically manipulated, they have also sometimes resulted in inadequate customized fluid handling and fit.
Patent literature in the tampon field has explored the use of different expansion restricting elements in a tampon absorbent design. For instance, various techniques have been described for creating different expansion shapes for digital tampon components. For example, various restrictive elements have been used to wrap the withdrawal end of a tampon absorbent so as to limit expansion of the tampon in this region. The literature has suggested that by maintaining a smaller diameter withdrawal end following use, such tampons could more easily be removed from the vaginal canal, causing less discomfort to the user. See for example, the restrictive elements in U.S. Pat. No. 2,330,257 to Bailey; U.S. Pat. No. 3,038,214 Griswold et al.; and JP 2004-097304, EP 1481656, and EP 2184044. Some of the restrictive elements described include threads, rings or moisture impermeable overwrap materials which completely and tightly overwrap the withdrawal end of a tampon absorbent. Some of the hydrophobic or liquid impermeable overwraps described are also designed to form a cap on the withdrawal end, thereby limiting leakage during tampon absorbent removal. A further example of an overwrap may be found in WO2005/048901. Other methods for creating restrictive regions include the use of hydrophobic injectable materials, which limit the amount of menses that can be absorbed in particular areas of the tampon absorbent. For example, restrictive expansion using compositions impregnated into portions of the tampon structure is described in U.S. 2008/0154222 to Chaffringeon. The use of specific segmented grooves, voids or discontinuities along a tampon length to encourage fluid handling differences or absorbent channel enhancements at various regions of a tampon is described in U.S. 20110092940 to Fung et al. See also in this regard, U.S. 20080262463 to Noel et al. Even with such diverse designs for tampon restriction elements, there is still a need for tampon absorbents which provide for more efficient usage of their entire structure.
Some patent references also describe the use of various bending- influencing features along a tampon length such as in U.S. Pat. No. 2,858,831 to Graham, Jr. Such features include fiber orientation and disk segmentation/discontinuities. Even with such bending features, there is still a need for improved comfort of tampon absorbents.
While various types of absorbent enhancement structures or restrictive structures have been described in the foregoing references, these references focus on use of either single ribbon structures or overwrapping absorbent layered structures in which absorbent sheets are substantially positioned one on top of the other along the entire tampon length, such that the type(s) of absorbent along the finished length of a tampon absorbent (facing the vaginal canal) is essentially the same along the entire length dimension, the exception being tampon absorbents with topographical patches (or islands) of different materials. Essentially, such tampon absorbents demonstrate similar absorbency functionality along their entire length and are formed via bonding in the longitudinal direction of the tampon. In addition to functional disadvantages of such structures, the manufacturing processes for creating such structures pose layer registration challenges.
There remains a need for a tampon and tampon absorbent product that prevents leakage of body fluid soon after being inserted into a woman's vagina, provides efficient utilization of the entire absorbent structure during use, without the necessary use of blocking agents or extraneous chemistry, or physical structures, and which also provides for comfort to a user throughout various daily activities.